Studies on the Composition of Respiratory Mucus started under Contract NO1-HR-52956 will be continued. Detailed structural studies on canine tracheal mucus obtained from subcutaneous closed tracheal pouches will be completed. Human tracheobronchial mucus will be obtained by fiberoptic bronchoscopy. Alveolar secretions will be investigated in effluents from lung lavage. Respiratory secretions from normal volunteers and from patients with such diseases as cystic fibrosis, emphysema, chronic bronchitis, bronchiectasis, asthma and alveolar proteinosis will be investigated. Sputum will be used, if necessary, as a potential source for the large-scale isolation of pathological materials of interest detected in the specimens obtained by bronchoscopy and lavage. The respiratory secretions will be fractionated by a combination of techniques such as fractional precipitation with organic reagents, column chromatography (gel filtration, adsorption, ion-exchange, affinity), isoelectric focusing and gel electrophoresis. The homogeneous glycoprotein components will be subjected to chemical studies to establish the composition and structure of the prosthetic group(s) and the nature of their linkage to the polypeptide chain. These studies will involve the preparation of homogeneous glycopeptides and/or the isolation of the heterosaccharide(s) followed by classical structural studies using techniques such as progressive acid hydrolysis, mildalkaline treatment, periodate oxidation, Smith degradation, permethylation, and sequential degradation with specific glycohydrolases. In addition to detailed chemical studies on the composition and structure of the carbohydrate moiety of normal and pathological respiratory glycoproteins, non-covalent interactions among the glycoproteins themselves and with other components of the respiratory mucus will be investigated. The effect of these interactions on the viscosity of solutions containing well defined mixtures of the mucus components will be evaluated. These studies are essential for the elucidation of the factor(s) responsible for the abnormal viscoelastic properties of pathological respiratory secretions.